pretty much every part of the installation. Ive set up all enviroment variables, put lejos on my C folder. One thing that comes to mind is installing the lego tower, I have no idea how to do that and neither do those guides. All it says is to make the enviroment variable which I did.

I fixed the usb tower issue but now I cant upload anything to my rcx, the firmware upload works fine but when I try to upload a java file it gives me this error.

Exception reading upload
js.classfile.EClassFileForma: Version not recognized: 50.0
at js.classfile.JClassFile.readMagicandVersions<JClassFile.java:226>
at js.classfile.JClassFile.read<JClassFile.java:255>
at js.tinyvm.ClassRecord.getClassRecord<ClassRecord.java.427>
at js.tinyvm.Binary.processClasses<Binary.java:91>
at js.tinyvm.Binary.createFromCloserOf<Binary.java:258>
at js.tinyvm.TinyVM.main<TinyVM.java:109>
at js.tinyvm.TinyVM.main<TinyVM.java:100>
at js.tinyvm.TinyVM.main<TinyVM.java:217>
at js.tinyvm.TinyVM.main<TinyVM.java:251>

I am having trouble with installing the firmware. i did exectly what the tutorial said. The error that comes up when i launch firmdl.bat is: Exception in thread "main" java.lang.NoClassDefFoundError: js/tools/Firmdl

i set all variables correctly without issues, have the correct JDK installed and i set RCXTTY to usb. I hav no idea why i am getting this messege.

Help

PS: For uploading programs the RCX, try using Bricx Command Center. I have heard it is really good.

I found out the problem. Every time i use software that uses the ir tower, my computer crashes (brixc command center, RIS etc.). I found out that i didn't have the latest ir tower driver (i was using the one from the Mindstorms for Schools set).

This should be fixed by this link and clicking on download and installing it.